Argentinosaurus is a genus of giant sauropod dinosaur that lived during the Late Cretaceous period in what is now Argentina. Although it is only known from fragmentary remains, Argentinosaurus is one of the largest known land animals of all time, perhaps the largest, measuring 30–35 metres (98–115 ft) long and weighing 65–80 tonnes. It was a member of Titanosauria, the dominant group of sauropods during the Cretaceous. It is widely regarded by many paleontologists as the biggest dinosaur ever, and perhaps lengthwise the longest animal ever, though both claims have no concrete evidence yet.
Titanosaurs were a diverse group of sauropod dinosaurs, including genera from all seven continents. The titanosaurs were the last surviving group of long-necked sauropods, with taxa still thriving at the time of the extinction event at the end of the Cretaceous. This group includes some of the largest land animals known to have ever existed, such as Patagotitan—estimated at 37 m (121 ft) long with a weight of 69 tonnes —and the comparably-sized Argentinosaurus and Puertasaurus from the same region.
Nemegtosauridae is a family of titanosaurian sauropod dinosaurs based on their diplodocid-like skulls. Only three species are known: Nemegtosaurus, Quaesitosaurus and possibly Tapuiasaurus, each from the Cretaceous.
Sanpasaurus is a poorly known sauropod dinosaur from the Early to Late Jurassic of Sichuan, China. The type species, S. yaoi, was described by Chung Chien Young, in 1944. The type remains, IVPP V.156, consists of 20 vertebrae, scapulae, forelimbs, and some hindlimb bones. Initially reported by Young as an ornithopod ornithischian, this specimen was unambiguously referred to Sauropoda in 2016 by McPhee et al., later refined to a basal gravisaurian position by Pol et al. in 2020 and 2022, closely related to Vulcanodon and Tazoudasaurus. Sanpasaurus is known from remains recovered from the Maanshan Member of the Ziliujing Formation.
Isisaurus is a genus of titanosaurian dinosaur from the Late Cretaceous Lameta Formation of India and Pab Formation of Pakistan. The genus contains a single species, Isisaurus colberti.
Futalognkosaurus is a genus of titanosaurian dinosaur. The herbivorous Futalognkosaurus lived approximately 87 million years ago in the Portezuelo Formation, in what is now Argentina, of the Coniacian stage of the late Cretaceous Period. The fish and fossilized leaf debris on the site, together with other dinosaur remains, suggest a warm tropical climate in Patagonia during this period.
Mendozasaurus is a genus of titanosaurian sauropod dinosaur. It was a member of Titanosauria, which were massive sauropods that were common on the southern landmasses during the Cretaceous. It is represented by several partial skeletons from a single locality within the Coniacian Sierra Barrosa Formation in the south of Mendoza Province, northern Neuquén Basin, Argentina. The type species, Mendozasaurus neguyelap, was described by Argentine paleontologist Bernardo Javier González Riga in 2003. Mendozasaurus is the first dinosaur named from Mendoza Province, Argentina, for which it was named.
Puertasaurus is a genus of sauropod dinosaur that lived in South America during the Late Cretaceous Period. It is known from a single specimen recovered from sedimentary rocks of the Cerro Fortaleza Formation in southwestern Patagonia, Argentina, which probably is Campanian or Maastrichtian in age. The only species is Puertasaurus reuili. Described by the paleontologist Fernando Novas and colleagues in 2005, it was named in honor of Pablo Puerta and Santiago Reuil, who discovered and prepared the specimen. It consists of four well-preserved vertebrae, including one cervical, one dorsal, and two caudal vertebrae. Puertasaurus is a member of Titanosauria, the dominant group of sauropods during the Cretaceous.
Lithostrotia is a clade of derived titanosaur sauropods that lived during the Early Cretaceous and Late Cretaceous. The group was defined by Upchurch et al. in 2004 as the most recent common ancestor of Malawisaurus and Saltasaurus and all the descendants of that ancestor. Lithostrotia is derived from the Ancient Greek lithostros, meaning "inlaid with stones", referring to the fact that many known lithostrotians are preserved with osteoderms. However, osteoderms are not a distinguishing feature of the group, as the two noted by Unchurch et al. include caudal vertebrae with strongly concave front faces (procoely), although the farthest vertebrae are not procoelous.
Malarguesaurus is a genus of titanosauriform sauropod dinosaur from the Late Cretaceous of Mendoza Province, Argentina. Its fossils, consisting of tail vertebrae, chevrons, ribs, and limb bones, were found in the upper Turonian-lower Coniacian Portezuelo Formation of the Neuquén Group. The type species, described by González Riga et al. in 2008, is M. florenciae.
Aeolosaurini is an extinct clade of titanosaurian dinosaurs known from the Cretaceous period of Argentina and Brazil. Rodrigo M. Santucci and Antonio C. de Arruda-Campos (2011) in their cladistic analysis found Aeolosaurus, Gondwanatitan, Maxakalisaurus, Panamericansaurus and Rinconsaurus to be aeolosaurids.
Eutitanosauria is a clade of titanosaurs, encompassing the more derived members of the group and characterized by the absence of the hyposphene-hypantrum articulation and possibly the presence of osteoderms. The group was first named by Sanz and colleagues in 1999, who used it to unite the group of Argyrosaurus, Lirainosaurus, Saltasaurus and the Peiropolis titanosaur. However, this definition was not used as it made the group equivalent to Saltasauridae, so Saldago redefined it in 2003 to be all titanosaurs closer to Saltasaurus than Epachthosaurus. This definition created Eutitanosauria as the sister group to Epachthosaurinae, but was problematic due to the variable nature of Epachthosaurus. Eutitanosauria was often broadly similar to Lithostrotia, and has often been unused or unlabelled on phylogenies. Sometimes Epachthosaurus would be more primitive than Malawisaurus, making Eutitanosauria more encompassing than Lithostrotia, or Epachthosaurus could nest close to Colossosauria and limit Eutitanosauria to a smaller group of saltasauroids. Because of the flexible nature of Epachthosaurus in basal titanosaur phylogeny, Carballido and colleagues redefined the group in 2022 to include the smallest clade of both Patagotitan, a colossosaur, and Saltasaurus, creating a node-stem clade with Colossosauria and Saltasauroidea, presenting the informal cladogram of stable titanosaur clades below.
Brasilotitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous Adamantina Formation of Brazil. The type species is Brasilotitan nemophagus. Brasilotitan was a small titanosaur with a squared-off snout, and may be closely related to another Brazilian titanosaur, Uberabatitan.
Quetecsaurus is a genus of titanosaurian sauropod dinosaur known from the Late Cretaceous of the southern Mendoza Province, western Argentina. It contains a single species, Quetecsaurus rusconii.
Patagotitan is a genus of titanosaurian sauropod dinosaur from the Cerro Barcino Formation in Chubut Province, Patagonia, Argentina. The genus contains a single species known from at least six young adult individuals, Patagotitan mayorum, which was first announced in 2014 and then named in 2017 by José Carballido and colleagues. Preliminary studies and press releases suggested that Patagotitan was the largest known titanosaur and land animal overall, with an estimated length of 37 m (121 ft) and an estimated weight of 69 tonnes. Later research revised the length estimate down to 31 m (102 ft) and weight estimates down to approximately 50–57 tonnes, suggesting that Patagotitan was of a similar size to, if not smaller than, its closest relatives Argentinosaurus and Puertasaurus. Still, Patagotitan is one of the most-known titanosaurs, and so its interrelationships with other titanosaurs have been relatively consistent in phylogenetic analyses. This led to its use in a re-definition of the group Colossosauria by Carballido and colleagues in 2022.
Notocolossus is a genus of titanosaurian sauropod dinosaur from late Cretaceous strata of Mendoza Province, Argentina.
Rinconsauria is an extinct clade of giant titanosaurian sauropods known from the late Cretaceous period of Argentina.
Colossosauria is a clade of titanosaur sauropods from the latest Early Cretaceous through the Late Cretaceous of South America. The group was originally named by Bernardo González-Riga et al. in 2019 and defined as the "most inclusive clade containing Mendozasaurus neguyelap but not Saltasaurus loricatus or Epachthosaurus sciuttoi". The clade contains different taxa depending on the phylogenetic analysis used, in the defining paper the only subgroups were Rinconsauria and Lognkosauria, but alternate phylogenies published previously had also included various similar titanosaurs such as Aeolosaurus, Bonitasaura, Drusilasaura, Overosaurus and Quetecsaurus. The phylogenetic analysis of González-Riga et al. (2019) placed Colossosauria as sister taxa to Epachthosaurus, Pitekunsaurus and a larger clade including Saltasauridae.
Diamantinasauria is an extinct clade of somphospondylan titanosauriform sauropod dinosaurs with close affinities to the Titanosauria, known from the early Late Cretaceous (Cenomanian-Turonian) of South America and Australia. It was named by Poropat and colleagues in 2021, and contains four genera: Australotitan, Savannasaurus and Diamantinasaurus from the Winton Formation of Queensland, as well as Sarmientosaurus from the Bajo Barreal Formation of Patagonia. The existence of the clade indicates connectivity between Australia and South America via Antarctica during the Cretaceous period.
Saltasauroidea is a superfamily of titanosaurs named by França and colleagues in 2016 based on their phylogenetic results, for a clade uniting Aeolosaurini and Saltasauridae, as well as the intermediate genera Baurutitan, Diamantinasaurus and Isisaurus. The group was not defined or discussed in the text, but was supported by Carballido and colleagues in 2022 as a useful designation for subdividing titanosaurs. As there was no discussion about the intentions for the clade, Carballido gave it the definition of all taxa closer to Saltasaurus than Patagotitan, encompassing half of Eutitanosauria as the sister taxon to the inversely defined Colossosauria. Carballido et al. placed Nemegtosauridae and Saltasauridae within the group, though they had Aeolosaurini within Colossosauria. The informal cladogram of titanosaur relationships they proposed is shown below.
